Pattern recognition system

ABSTRACT

A pattern recognition system scans an unknown pattern to detect moments of successive slices or portions of the pattern. Certain of these moment signals are selected in various sections of the pattern to obtain comparison parameters based on characteristics of the sections. These comparison parameters and parameters for reference patterns are compared to identify the unknown pattern.

v United States Patent 11 1 1111 3,46,755

Hart Nov. 5, 1974 PATTERN RECOGNITION SYSTEM 3,159,815 12/1964 Groce 340/146.3 AG

3,268,864 8/1966 Kubo et al 340/l46.3 AB [75] lnvemor- Mass- 3,292,148 12/1966 GilliiallO et al. 340/146.3 o 73 Assignee; Electronic Reading Systems 3,394,347 7/1968 Crane 356/71 Watertown, Mass.

[22] Filed: Aug. 6, 1973 Primary Examiner-,Gareth D. Shaw 21 A l. N 385 713 Assistant Examiner-Leo l-l. Boudreau l 1 PP 0 1 Attorney, Agent, or Firm-Cesan and McKenna Related US. Application Data [63] Continuation-impart of Ser. No. 93,378, Nov. 27,

1970, which is a continuation-in-part of Ser. No. 885,044, Dec. 15, 1969, abandoned. [57] ABSTRACT Cl 340/146-3 A pattern recognition system scans an unknown patm y 3 4QL1 4 6.3 I-l tern to detect moments of successive slices or portions -l k /13 of the pattern. Certain of these moment signals are se- [58] Field of Search ..340/146.3 H, 146.3 R, lected in various sections of the pattern obtain com- 340/ 146.3 AG, 146.3 G, 347 AD; parison parameters based oncharacteristic s of the sec 356/71; 235/183 tions. These comparison parameters and parameters for reference patterns are compared to identify the [56] References Cited unknown pattern.

UNITED STATES PATENTS 3,146,424 8/1964 Peterson et al. 340/347 AD 23 Claims, 59 Drawing Figures so 1640 164b 1 I 11 T6 'Tm 17 2 'L1| 64 +uP-DowN THRESHOLD COUNTER CIRCUIT COUNTER QUANTF'ER 1 DIVIDER QUOTIENT s1/so ANALYZER R I68 640 I 176 I74 1 S1 ue-oowu THRESHOLD s 1 COUNTER CIRCUIT R DECODER l [I64 R 164C 19a \YEWZ +5174 656 I62 OVERRIDE CLOCK CIRCUIT COUNTER +1: 178 82 /"T" I80 82b ,192 l 1 THRESHOLD 1 QUOTIENT 4% $363??? CIRCUIT COUNTER 1 $2 /$0 ANALYZER I 1 l t I86 19s THRESHOLD S l s2 1 ea-COUNTER CIRCUIT R o l 1 1 1e4 IBZ/C COUNTER 1 E194 l l 1 1 GNA PROCESSING SECTI N g PAIENTEDIIIII 51914 3.846.755

sum 01 0F 23 CHARACTERS DIFFERENTIATING CORRESPONDING OPTICAL CHARACTERISTIC PHYSICAL CHARACTERISTIC 'V, v SIZE MASS r q SIZE AND BALANCE MASS AND BALANCE 9, 6 BALANCE BALANCE 1 7 SLENDERNESS DISPERSION, BALANCE I, Q CENTRALNESS 0F, DISPERSION RELATIVE AREA DISTRIBUTION -TO CENTER OF GRAVITY I 5 DENSITY I DISPERSION sum 02 or 23,

DIRECTION OF SLIT MOVEMENT FIG. 2 A FIRST x VERTICAL MOMENT SIGNAL(SI) VOLTS E as VOLTS E A2 (TOTAL ZERO MoMENT 9| AREA UNDER E 85 SIGNAL (SD) x CU V E E 90 AI (TOTAL AREA UNDER CURVE) WW MFA FIG 26 FIG. 2B

' E c J TEDNTAL VOLTS MOMENT SECOND SIGNAL (83) SIGNAL (s2) A4(TOTAL AREA UNDER A3 TOTAL URVE 92 AREA UNDER 0 CURVE) E82 FIG. 2E

FIG. 20

PATENIEUNHY 5l974 3,846,755

sum 03 or 23 SECOND HORIZONTAL (Egg VOLTS MOMENT VOLTS MOMENT SIGNAL (s4) A5(TOTAL AREA UNDER CURVE) AREAS E94 FIG. 26

FIG' 2F FIRST HORIZONTAL MOMENT SIGNAL (s3 VOLTS ENTI AR VOLTS AL MOMENT RE EA NON MAXIMUM AREA OF AREAs g :3! el- 95 FIG. ZJ

FIG. 2H

FIG. 2K

PAIENIEIJRUV s m 3,846,755

sum nu Bf 2a I NARROW AREA VOLTS AT MIDPOINT FIRST VERTICAL E304 VOLTS MOMENT AT MIDPOINT E305 zERO MOMENT I SIGNAL (sO) 4 WEIT 3%: SIGNAL (3:)

FIGZL O I 3 E IIBA R L VOLTS MOMENT" SIGNAL(S2) SECOND VERTICAL HAND SEC-HON MOMENTAT I MIDPO'NT E306 VOLTS OF CHARACTER O WMAX 2 V F I G 2N AREAS OF PORTIONS OF MAXIMUM SOLID HEIGHT IN LEFT HAND SECTION OF CHARACTER E308 FIRST VERTICAL MOMENT SIGNAL (SI) SUM OF FIRST VERTICAL MOMENT SIGNAL FOR PORTIONS IN SECOND HALF OF CHARACTER WITH EXACTLY TWO LINES E3IO SUM OF FIRST VERTICAL VOLTS g MOMENT SIGNAL FOR WM SECTIONS IN sECONO 3 HALF OF CHARACTER PATENTEDIIBV 5l974 $346,755

sum 050F213;

GLOBAL CHARACTERISTICS CENTROID I I 1 EL he h max B-- ----e 4 \:{C l

C w C f FIGBA COMPONENT CHARACTERISTICS HIGHEST MAXIMUM VERTICAL SECTIONS (2 REGIONS) E IIE 'I MXQ PORTION T- h max B B ww- GROUPS OF MAXIMUM VERTICAL VERTICAL PORTIONS PORTION F IG. 3C

GREATER VERTICAL PORTIONS MINIMUM VERTICAL SECTION LYING BETWEEN GREATER VERTICAL PORTIONS MINIMUM SECTION A VERTICAL CENTROID I RADIUS OF PAIENTEIJIIIIII 5I9I4 3346755 SHEEI us [If 23 l I VERTICAL I PORT IO N No @JTINUOUS H q B I VALUE OF I CT DERIVATIVE O I -"-I EII=I TIoII IIIOQIIaI IENT I FIOBN coNTINuOus SECTION F|G3M VALUE OF DERIVATIVE LETTER N AND DERIVATIVE OF LOCUS OF CENTROID I.

LOCUS OF RADIUS OF GYRATION HEIGHT OF DERIVATIVE OF LOCUS OF RADIUS OF GYRATION ABOUT OF VERTICAL AxIs B-B OF A VE TICAL igflgfi w PORTION IN LETTERR'A" FIGBR FIG.3P

VALUE OF 0 B B DERIvATIvE VALUE OF DERIVATIVE 0 LETTER K'AND DERIvATIvE OF FIGBS LOCUS OF RADIUS OF GYRATION ABOUT AXIS'B-B LETTER"0"AND DERIvATIvE OF RADIUS OF GYRATION OF VERTICAL SECTION PATENTEDIIIIV SIIIII $846755 sum 07 HF 23 WHICH CONTAIN PORTIONS EXHIBITING NON MAXIMUM MAXIMUM SOLID AREA OF LETTER HEIGHT (PORTIONS) A (4 PARTS) ARE INDICATED CHARACTER AREAS BY DoTTED LINEs) c I non m0 CENTRDID OF I 3 NW MAXIMUM m x AREA I I C H636 F|G.3F

DEVELOPMENT CHARACTERISTICS LOCUS OF CENTRoID HEIGHT I CENTIROID VERTICAL I OF PORTION I VERTICAL PORTION I max *I Q I DIRECTION OF o w PoRTIoN MOVEMENT HoRIzoNTAL LocAT Ig g o wE RTICAL FIGBH FIG.3WJ

' VALUEOF 'l DERIVATIVE o CONTINUOUS OF LOCUS SECTION OF V CENTROID VALUE 0F I DERIVATIVE DERIVATIVE VALUES FOR Locus OF LOCUS o 1 OF CENTROID 0F VERTICAL I OF sECTIoNs IN LETTER "A" cENTRoID I Y LETTER II .I NoN CONTINUOUS FIGBK FIGZIL I LETTER "M" ND DERIVATIVE sum 0a or 23 PORTlONS IN SECOND HALF OF CHARACTER WHICH EXHIBIT TWO OR MORE LINES PORTIONS IN SECOND HALF OF CHARACTER WHICH EXHIBIT EXACTLY Y FIG.3Y

B TWO LINES V w gmx w g/IAX w MAX w MAX V J B 5 w MAXB FIG 3Z w MAX w AX 2 A WMAX g PAIENTEDNIN 519M SHEET 09 0f 23 GLOBAL CHARACTERISTICS CHARACTERISTIC NAME SYMBOL DEFINITION MAXIMUM SOLID HEIGHT MAXIMUM WIDTH VERTICAL CENTROID HORIZONTAL CENTROID VERTICAL RADIUS OF GYRATION HORIZONTAL RADIUS 0F GYRATION s max MAXIMUM OF SOLID OR COMPRESSED HEIGHT OF THE CHARACTER THE MAGNITUDE EXCLUDES ANY NON- CHARACTER (FIELD) HEIGHT wHIcH MIGHT BE INCLUDED BY A VERTICAL sEcTIoN. (FIGS.

TOTAL wIDTH OF cHARAcTER (FIG. 3A)

DISTANCE OF THE CENTROID FROM THE LEFT-HAND VERTICAL AXIS (C-C IN FIG 3A) OF A CHARACTER R DIus 0F GYRATION ABOUT THE cENTER OF GRAVITY (FIG .38)

RADIUS OF GYRATION ABOUT THE LEFTHAND AxIs (c-c) (FIG. 3B)

FIG.4

F) A IAIENTEDRB 5AA 3.846.755

sum 10 III 23 COMPONENT CHARACTERIsTICs CHARACTERIsTIC NO. NAME SYMBOL DEFINITION l MAXIMUM sECTION VERTICAL DISTANCE FROM THE BOTTOM CENTROID max AXIs(B-B) TO THE CENTROID OF THE HIGHEST MAXIMUM SECTION. (FIF. 3D)

2 MINIMUM SECTION VERTICAL CENTROID DISTANCE FROM THE BOTTOM XIs (B-B) TO THE CEN ROID OF THE MINIMUM sECTION (FIG. 3E)

3 MINIMUM SECTION VERTICAL RADIUS 0F GYRATION OF RADIUs OF GYRATION min MINIMUM sECTIoN ABOUT CENTER OF GRAVITY OF THAT SECTION.

4 VERTICAL CENTROID OF DISTANCE FROM THE BOTTOM NON-MAXIMUM sECTION charm AXIs TO THE CENTROID OF THAT AREA OF A CHARACTER wHICH REMAINs AFTER ALL MAXIMUM SOLID HEIGHT sECTIONs ARE EXCLUDED.

5 HORIZONTAL CENTROID OF DIsTANCE FROM THE LEFT HAND NON-MAXIMUM SECTION C On "MUX AXIs OF A CHARACTER (C-C) TO THE CENTROID OF THE NON MAXIMUM sECTION AS DEFINED BY NON-MAX. (FIG. 36)

PAIENIEDIIIN 5 I974 SHEH 11 SPECIAL CASE COMPONENT CHARACTERISTICS CHARACTERISTIC SYMBOL DEFINITION NO I NAME 6 MIDPOINT vERTIcAL g mpt RADIUs OF GYR T ON OF A PORTION RADI 0F GYRATION LOCATED AT THE CENTER OF THE cHARAcTER ABOUT THE cENTER OF GRAVITY OF THAT PORTION (FIGURE 3U).

7 AREA OF LEFT HAND s Hs AREA OF IMAGE LOCATED BETWEEN SECTION ITs LEFT HAND EDGE AND A vERTIcAL AXIS PAssING THROUGH A POINT ONE THIRD OF THE WAY AcROss THE wIDTH OF THE cHARAcTER (FIGURE 3W) 8 MAXIMUM AREA OF smclx fls AREA OF PORTIONS I EXHIDITING LEFT HAND SECTION MAXIMUM sOLID HEIGHT IN THE LEFT HAND sEcTION OF A CHARACTER (As DEFINED ABOVE) THIs MAXIMUM SOLID HEIGHT IS THE MAXIMUM sOLID HEIGHT IN THE LEFT HAND sEcTION (FIGURE 3X) 9 vERTIcAL FIRsT MOMENT TOTAL FIRST ORDER MOMENT ABOUT FOR PORTIONS CONTAIN m m THE BOTTOM AXIS (B-B) OF THESE Two LINES IN SECOND H L PoRTIONs IN THE RIGHT sEcTION OF cHARAcTER OF THE cHARAcTER IN wHIcH THE PORTIONs EvIDENcE EXACTLY Two LINES (FIGURE 10 VERTICAL FIRST MOMENT FOF TOTAL, FIRST ORDER MOMENT ABOUT PORTIONS CONTAININ TWO is THE BOTTOM AXIS (B-B) OF THEsE OR MORE LINEs IN sEcOND lunzz) PORTIONS IN THE sEcOND HALF OF HALF OF CHAR THE CHARACTER IN wHIcH THE PORTIONS EVIDENCE Two OR MORE LINEs. (FIGURE 32).

FIG.6

PAIENIEUNUV 5 m4 5 saw 12 or 23 MINIMUM SECTION GYRATION HEIGHT TYPICAL TYPICAL GEOMETR 1c CLASS OF CHARACTER EXAMPLES ELITE FONT BLOCK FONT VALUES VALUES 1 sLANT MEMBERS ONLY V, W .29 .29

2 INTERSECTING SLANT MEMBER X .15 .15

3 SINGLE MEMBER BETWEEN VERTICAL MEMBERS H, N .06 .09

l SINGLE BAY CLOSED BY VERTICAL LINE D .95 A3 5 DOUBLE BAY CLOSED BY VERTICAL LINE B .37 .35

FIG.?

PATENTEDNUY 5 91 sum 1a or 23 CIRCUIT 220 9 (FIGURE 19) Ll GH T TRANSMISSION DISTANCE ABOVE? BOTTOM OF FILTER FIG. IO

58b, 59b, 60b 

1. A method of identifying an unknown pattern comprising the steps of: A. measuring a plurality of moments about at least one predetermined axis in each of successive portions of the pattern, at least two of the moments being different moments with respect to the same axis, B. generating a moment signal corresponding to the value of each of the measurements, C. selecting certain of the moment signals indicative of predetermined characteristics of the pattern in sections thereof less than the entire pattern, D. generating a plurality of comparison parameter signals including comparison parameter signals for the sections, at least one of the comparison parameter signals for a section being generated by taking a ratio of said moment signals, at least one moment signal for that ratio being a preselected moment signal for that section, and E. comparing the values of the comparison parameter signals with corresponding values of reference patterns to identify the unknown pattern.
 2. A method as recited in claim 1 wherein said selecting step includes the selection of moment signals in sections of the pattern which produce maximum and minimum values of a moment signal and said comparison parameter signal generating step additionally generates signals corresponding to the value of a moment signal for those sections.
 3. A method as recited in claim 1 wherein said measuring and moment signal generating steps develop signals representing moments of a pattern about a first axis, said moment signal generating step additionally including generating signals representing moments of the pattern about a second axis perpendicular to the first axis.
 4. A method as recited in claim 1 wherein said moment signal generating step inclUdes: i. generating a moment signal proportional to the area of the pattern in each portion, and ii. generating a moment signal proportional to the aggregate distance of the pattern area in each portion from an axis perpendicular to the direction of succession of the portions.
 5. A method as recited in claim 4 wherein said moment signal generating step additionally includes generating a moment signal disproportionate to the aggregate distance.
 6. A method as recited in claim 1 wherein said selecting step includes the selection of moment signals in sections of the pattern which produce maximum and minimum values of a moment signal and said comparison parameter signal generating step additionally generates signals corresponding to the integrals over sections of moment signals in the sections.
 7. A method as recited in claim 6 wherein said selecting step includes the selection of moment signals in other sections of the pattern which produce moment signal values which are other than maximum and minimum values and said comparison parameter signal generating step additionally generates comparion parameter signals corresponding to integrals over sections of moment signals in the other sections.
 8. A method as recited in claim 1 wherein at least one comparison parameter signal represents a comparison of moment signals representing moments of different sections of the pattern.
 9. A method as recited in claim 6 wherein in one section the selected moment signal is a maximum and in another section a selected moment signal is a minimum.
 10. A method as recited in claim 1 wherein said moment signal generating step includes: i. generating a moment signal proportional to the area of the pattern in each portion, and ii. generating a moment signal proportional to the aggregate distance of the pattern area in each portion from the predetermined axis, the predetermined axis being parallel to the direction of succession of the portions.
 11. A method as recited in claim 10 wherein said moment signal generating step additionally includes generating a moment signal disproportionate to aggregate distance from the predetermined axis.
 12. A system for identifying a pattern, said system comprising: A. means for measuring a plurality of moments about at least one predetermined axis in each of successive portions of the pattern, at least two of the moments being different moments with respect to the same axis, B. means connected to said measuring means for generating a moment signal corresponding to the value of each measured moment, C. means for selecting certain of the moment signals indicative of predetermined characteristics of the pattern in sections thereof less than the entire pattern, D. means connected to said moment signal generating means and said selecting means for generating a plurality of comparison parameter signals including comparison parameter signals for the sections, at least one of the comparison parameter signals for a section being generated by taking a ratio of the moment signals, at least one moment signal for that ratio being a preselected signal for that section, and E. means connected to said comparison parameter signal generating means for comparing the values of the comparison parameters with corresponding values of reference patterns to identify the unknown pattern.
 13. The system defined in claim 12 in which said comparison parameter signal generating means includes means for generating a signal representing the centroid position of a section of the pattern in which the zero order moment is other than a maximum, the centroid position being obtained from the zero and first order moment signals.
 14. The system defined in claim 12 in which the moment signals correspond to the zero, first and second order moments with respect to the axis, said measuring means additionally including i. means for developing time signals representing the elapsed time from commencement of the measurinG of said moments and the square of the elapsed time, and ii. means for multiplying said zero moment by said time signals to provide further moment signals corresponding to the first and second order moments of said portions about a second axis tranverse to said first axis.
 15. The system defined in claim 12 A. said selecting means including means for detecting the occurrence of maxima of at least one of said moment signals, and B. said comparison parameter signal generating means including means for counting the number of maxima of each moment for which the maxima are detected, the output of said counting means constituting a comparison parameter signal.
 16. The system defined in claim 12 in which said selecting means includes means for selecting moment signals in a section corresponding to the occurrence of the peak value of one of said moment signals and said comparison parameter generating means includes means for integrating over sections a plurality of the moment signals in the sections.
 17. The system defined in claim 16 in which said selecting means includes means for selecing moment signals in other sections in which a selected moment signal is at other than the peak value said compison parameter signal generating means includes means for integrating over sections a plurality of the moment signals in the sections corresponding to the other sections.
 18. The system defined in claim 12 in which the moment signals represent the zero, first and second order moments, said comparison parameter signal generating means additionally including A. means for obtaining a first ratio of the first moment signal to the zero moment signal, and B. means responding to changes in the value of the first ratio to provide a signal indicating the presence of a single slope signal in said pattern.
 19. The system defined in claim 18 wherein said comparison parameter signal generating means further includes A. means for obtaining a second ratio of the second moment signal to the zero moment signal, and B. means responding to changes in the value of the second ratio to provide a double slope signal responsive to a double slope in said pattenr.
 20. A system as recited in claim 12 wherein said moment signal generating means includes: i. means for generating a moment signal proportional to the area of the pattern in each portion, and ii. means for generating a moment signal proportional to the aggregate distance of the pattern area in each portion from the predetermined axis, the predetermined axis being parallel to the direction of succession of the portions.
 21. A system as recited in claim 18 wherein said moment signal generating means additionally includes means for generating a moment signal disproportionate to the aggregate distance.
 22. A system as recited in claim 12 wherein said moment signal generating means includes i. means for generating a moment signal proportional to the area of the pattern in each portion, and ii. means for generating a moment signal proportional to the aggregate distance of the patern area in each portion from an axis perpendicular to the direction of succession of the portions.
 23. A system as recited in claim 22 wherein said moment signal generating means additionally includes means for generating a moment signal disproportionate to the aggregate distance. 